BANGKOK, Aug 7 (Reuters) - Thai authorities are investigating the discovery of nine surrogate babies in a Bangkok condominium who are believed to share the same Japanese biological father, police said on Thursday.

The case is the latest to emerge after an Australian couple were accused of leaving a Down syndrome baby with his Thai birth mother, triggering global condemnation and calls for an overhaul of lax surrogacy laws.

Authorities acting on a tip-off raided the condominium in the Lat Phrao area of the Thai capital on Tuesday to find nine babies being looked after by seven nannies, with a pregnant 20-year-old living there.

Police spoke to a Thai man who said he was the lawyer of a Japanese businessman who claims to be the babies' biological father, deputy national police chief Aek Angsananont said.

"We are questioning the nannies, as well as asking for cooperation from the Japanese embassy, to help conduct DNA testing," Aek told Reuters.

He added: "If the Japanese man admits that all the children are his babies, we would ask him why he wanted to have so many babies."

Reuters was unable to contact the Thai lawyer, Ratprathan Tulathorn, despite repeated attempts to reach him by telephone.

The latest case has raised fresh concerns over the ease with which foreigners can come to Thailand, which has no laws directly relating to surrogacy, to buy surrogacy services.

Although commercial surrogacy is barred by the code of conduct of the Medical Council of Thailand, the country is a top destination in Asia for fertility clinics and couples opting for surrogacy arrangements.

An official of the Ministry of Social Development and Human Security, who is part of the team investigating the latest case, said the nannies were hired for a monthly sum of 10,000 baht ($310), while the pregnant woman said she was hired for 300,000 baht ($9,313) to give birth.

"We are looking for evidence to determine whether this surrogacy case is illegal," said the official, who declined to be named because he was not authorised to speak to the media.

The case has raised concerns that Thailand is the centre of a lucrative but largely unregulated surrogacy business. Authorities have begun a nationwide crackdown on clinics offering surrogacy services to see if they follow regulations. (1 US dollar=32.2100 Thai baht) (Reporting by Apornrath Phoonphongphiphat; Editing by Amy Sawitta Lefevre and Clarence Fernandez)

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